SBIR-STTR Award

An innovative and cost-effective technique, based on physical scale-model testing at 1-g, is presented to evaluate the performance of the next generation penetrator missiles designed to take out underground structures. The sub-scale target, an engineered system, can be considered as underground facilities built using tunneling or cut-and-cover construction techniques in a geologic system with variable characteristics. The engineered system can be designed as a complex multi-level facility or simply a system of tunnels excavated at the same depth elevation. The overburden thickness above the potential target can vary from few meters to several tens of meters. The objective of the mission is defined by the launched missile penetrating to a desired depth, detonating or impacting, and producing shock waves impinging on the engineered system (tunnel). The success of the mission is defined by the ability of the penetrator missile to generate ground shocks of large enough magnitude to cause structural damage. Similitude laws are used to determine the relevant characteristics of the scaled-model geologic and engineered systems and those defining size and type of weapons.The proposed study is directed towards the development of an experimental and analytical methods followed by a field test program for performance assessment and design optimization of conventional penetrator weapons used for sure kill. The impingement may occur either side ways or towards the center-line of the underground facility to cause structural damage such as internal spalling of concrete support lining material. Damage assessment is made using the US Air Force EarthRadar.A novel method and cost-effective approach for performance assessment of weapons. Damage assessment for hardened underground structures subjected to penetrator weapons attack. A unique technique for simulating stress wave propagation in anisotropic geologic materials under controlled conditions

There is a growing interest by our adversaries to utilize underground facilities for production and storage of "weapons-of-mass destruction" (WMD) and military hardware. Mechanized or conventional excavation techniques are used for construction of these facilities depending on the local conditions and their intended use. The penetrator weapons are designed to take out these underground structures. However, to protect against penetrator attack, these facilities are build at greater depth in hard rock. Prediction of performance of the penetrator weapons is contingent on thorough understanding of weapon-rock mass, including joint, fractures and other geologic features, interaction. Success of a planned mission depends on our ability to predict the performance of the penetrator weapons by accounting for the site-specific characteristics of the geologic (host medium) and engineered (tunnel, cavity, etc) systems. The objective of this proposal is to develop and validate two generalized empirical equations for penetrator weapons performance assessment and prediction of degree of damage to the engineered system. Both equations accept the characteristics of the penetrator weapons and site-specific characteristics of the geologic and engineered systems as input parameters. A series of physical modeling experiments at 1-g on scaled modeled tunnels are proposed for validation of the formulated penetrator "response" and "degree-of-damage" equations.

Keywords:
Penetrators, Missiles, Tunnels, Rocks, Geology, Similitude, Scaled-Model, Closure